Device and method for forming, particularly with a hydraulic clamping device

ABSTRACT

Device for forming has at least one tool upper part, at least one upper matrix and at least one lower matrix. The device also has at least one tool lower part, at least one first clamping device and at least one second clamping device.

BACKGROUND OF THE INVENTION

[0001] This application claims the priority of German Application No. 100 47 467.5, filed Sep. 21, 2000, the disclosure of which is expressly incorporated by reference herein.

[0002] The present invention relates a process and method for forming, particularly with a hydraulic clamping device.

[0003] DE 4418922 describes a method and a device for forging a steel rotor. For the production process, a mold made of two halves which can be placed in a press is used. The two mold halves can be clamped before forming starts in such a way that there is no longer a mold line. When the mold is closed, the inner contour of the mold halves corresponds exactly to the final shape of the rotor. In one of the form halves, a central pressing plunger, whose diameter is somewhat smaller than the root diameter of the rotor, is guided so it can be moved axially.

[0004] Furthermore, DE 4426180 describes a method for the production of beveled gearwheels having gearing ready for installation. The gearwheels are formed by multistage forming in a vertical clamping multistage press with the forging die having a surface hardness of at least 50 Rockwell. The forming of the gearing is performed by lateral extrusion, which preferably begins before the mold halves are closed.

[0005] A clamping device is described in DE 19814487 for clamping original and forming molds, preferably in singly acting machines having an adjustable clamping force which is generated by the compression of hydraulic or mechanic spring elements during movement of the machine ram. The volume and the pressure in the hydraulic system remain constant upon the necessary clamping force being reached in the cylinders through the opening of the valves and the coupling of the pistons via the tie rods and the couplings with the ram, which ensures the maintenance of the clamping force between the hollow mold halves. The machine drive is completely relieved of the clamping force, and thus further clamping work, by the feedback of the clamping force via the pistons, the tie rods, the couplings, and the transverse yoke onto the ram, which allows a load-free movement of the locked mold.

SUMMARY OF THE INVENTION

[0006] An object of the present invention is to provide a forming device in which the filling of the mold functions reliably.

[0007] This object has been achieved according to the invention in that a device for forming comprises at least one tool upper half, an upper matrix and a lower matrix and a tool lower half and a first clamping device and a second clamping device. It is advantageous that the clamping force can be adjusted by the two clamping devices, which have different clamping forces, to the necessary compression force gradient which is required for complete mold filling of the tool.

[0008] In a further embodiment according to the invention, the first and the second clamping device each have an annular piston with a sleeve.

[0009] A still further embodiment according to the invention provides that the device has a thrust collar.

[0010] According to the invention, yet another embodiment has the device provided with at least one plunger. This plunger is advantageous, among other things, for ejection of the finished part from the tool.

[0011] Furthermore, a refinement according to the invention is provided in which the clamping device communicates with a bladder accumulator. Various clamping forces can be advantageously realized through the use of various accumulators. In still another refinement according to the invention, the device has a counter plunger.

[0012] An aspect of the invention according to the invention provides that the device has at least one ejector pin.

[0013] The object is also achieved according to the invention by a press for forming which has a forming device.

[0014] In one embodiment according to the invention, the press has at least one ram and at least one platen.

[0015] Another embodiment according to the present invention provides that the press has at least one ram ejector rod and at least one platen ejector rod.

[0016] The object is still further achieved according to the present invention by a forming method, with a forming device and/or a press as described above. It is advantageous that parts produced by this method can be manufactured very precisely due to the complete mold filling of the tool.

BRIEF DESCRIPTION OF DRAWINGS

[0017] Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings wherein:

[0018]FIG. 1 is a schematic elevator view of the forming device according to the present invention;

[0019]FIG. 2 shows the forming device according to FIG. 1 in the open state before forming;

[0020]FIG. 3 is a force-path trace of the forming procedure; and

[0021]FIG. 4 shows two FEM [finite element method] mesh diagrams.

DETAILED DESCRIPTION OF THE DRAWINGS

[0022] In FIG. 1, a ram 1 is illustrated over a platen 2 of a press for forming. On the lower side of the ram 1, a tool upper part 3 is located, which is in turn located above and/or over a tool lower part 4. On the lower side of the tool upper part 3, an upper matrix 5 is mounted in the tool upper part and is moved essentially in the direction of movement of the ram. The lower matrix 6 is located on and/or in the tool lower part, similarly to its counterpart located above, so that the matrix is essentially also movable in the direction of movement of the ram.

[0023] A counter plunger 7, which is located opposite to the plunger 8, can be moved longitudinally in the matrix 5 and the tool upper part 3. The plunger 8, which is located in the tool lower part 4, is surrounded by a ferrule 9. The upper ejector pin 10 is also longitudinally movable in the tool upper part 3 in such a way that it communicates with the counter plunger 7. The ram ejector rod 11 is longitudinally movable in the ram 1, so that during ejection the rod 11 contacts the ejector pin 10 to transfer the ejection impulse to the counter plunger 7, which in turn ejects the formed part out of the open tool.

[0024] A platen ejector rod 12, which relays its impulse during ejection to an ejector pin 13, also longitudinally movable essentially in the tool lower part 4, is longitudinally movable in the platen 2. The ejector pin 13 then communicates with three ejector pins 14 to relay their movement to the ferrule 9, which then ejects the formed part from the open tool.

[0025] A thrust collar 15 is located below the matrix 6. This thrust collar 15 causes, together with the clamping device 16 and the annular piston 1 with ferrule 18, a first clamping of the tool, with a longer path and a lower clamping force being necessary in this first variant, as can also be gleamed from curve 4 in FIG. 3.

[0026] This first clamping procedure is followed by a further clamping procedure, in which a shorter path and an additional, greater clamping force act on the tool, this can also be gleamed from curve 2 in FIG. 3. This further clamping procedure is triggered by annular piston 1 with ferrule 18 in such a way that the ferrule 18 acts upon the annular piston 19. In this way, there is an addition to the clamping forces, which ensures that the part to be formed completely assumes the predetermined contour in the closed forming mold. This procedure occurs in the clamping device 17 which communicates with an annular piston 19. The bladder accumulators 20, 21 communicate with the clamping devices 17, 16, respectively, in such a way that they have appropriately compressed air cushions available to ensure that the respective clamping procedures proceed as defined. In an alternative embodiment, the two-stage clamping device is located at least once in a multiple tool.

[0027] In another alternative embodiment, the two-stage clamping device is not located on the ram instead of the platen. Another alternative embodiment provides that a clamping device of this type is located both on the ram and on the platen.

[0028] An open former device for forming, before a forming operation, with an unformed part 22, which is placed in the open matrix 6, can be seen in FIG. 2. A ram 1 is illustrated over a platen 2 of a press for forming. The lower side of the ram 1 has a tool upper part 3, which is located above a tool lower part 4. An upper matrix 5 is located on the lower side of the tool upper part 3. The lower matrix 6, like its counterpart located on the other side, is located on and/or in the tool lower part 4. When the forming process begins, the matrix 5, including the elements affixed to it, moves toward its counterpart matrix 6. The matrices 5, 6 reach one another and thus close the open matrix parts so that they press against one another in a form fitting way. In the first step of the forming procedure, the ram 1, including the tool upper part 3 and the matrices 5, 6, work counter to the annular piston 18, which communicates with the bladder accumulator 20. In the course of this first forming step, the material of the formed part 22 which has reached the matrix walls in the meantime attempts to open the matrices 5, 6. The compression force trace of this first step is illustrated by curve 2 in FIG. 3.

[0029] In the further course of the forming procedure, the annular piston 18, including the elements located above it, namely matrices 5, 6, tool upper part 3, and ram 1, act on the annular piston 19 as soon as they reach the annular piston. Annular piston 19 communicates with the bladder accumulator 21. The force-path trace of this second step is illustrated by curve 4 in FIG. 3. The path to be covered by the first step is significantly larger than that of the second step. The counter plunger 7, which is located opposite to the plunger 8, is longitudinally movable in the matrix 5 and the tool upper part 3. The plunger 8, which is essentially located in the tool lower part 4, is surrounded by a ferrule 9. A ram ejector rod 11 is longitudinally movable in the ram 1 to contact the ejector pin 10 during ejection and transfer the ejection impulse to the counter plunger 7, which in turn ejects the formed part from the open tool.

[0030] The upper ejector pin 10 is located in the tool upper part 3 in such a way that it strikes against the counter plunger 7 and, in the present example, causes this counter plunger 7 to move out of the matrix 5.

[0031] When the forming procedure is finished, the counter plunger 7 thus helps the formed part to be removed from the matrix 5. A platen ejector rod 12 is longitudinally movable in the platen 2, which relays its impulse during ejection to an ejector pin 13, also longitudinally movable in the tool lower part 4. The ejector pin 13 then communicates with the three ejector pins 14 to relay their movement to the ferrule 9, which then ejects the formed part from the open tool.

[0032] A thrust collar 15 is located below the matrix 6. This thrust collar 15 causes, together with the clamping device 16 and the annular piston 1 with ferrule 18, a first clamping of the tool, with, in this first variant, a longer path and a lower clamping force being required, as can also be gleamed from curve 4 in FIG. 3.

[0033] This first clamping procedure is followed by a further clamping procedure, in which a shorter path and an additional, greater clamping force acts on the tool, as can also be gleamed from curve 2 in FIG. 3.

[0034] This procedure occurs in the clamping device 17 which communicates with annular piston 19. The bladder accumulator 20 and the bladder accumulator 21 communicate with the clamping devices 17, 16 in such a way that they have appropriately compressed air cushions available which ensure that the respective clamping procedures proceed as defined.

[0035] In an alternative embodiment, it is provided that piston accumulators are used instead of the bladder accumulators. It is advantageous in this case that these piston accumulators are smaller and, above all, can be used independent of position. A further alternative embodiment provides that, instead of the thrust collars provided, thrust pins are used, which are also located around the circumference.

[0036] These types of tools are, for example, used in eccentric or knee toggle presses.

[0037]FIG. 3 shows the curve traces 2, 4 of the two clamping processes. Upper image 1 in FIG. 4 shows an FEM mesh before forming, whereas lower image 2 in FIG. 4 shows an FEM mesh after forming to illustrate, among other things, the precise filling of the mold.

[0038] The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof. 

1. Forming device, comprising at least one tool upper part, at least one upper matrix operatively associated with the at least one tool upper part and at least one lower matrix, at least one tool lower part operatively associated with the at least one lower matrix, at least one first clamping device and at least one second clamping device operatively associated with the at least one tool lower part.
 2. Forming device according to claim 1, where at least one of the at least one first and second clamping device has at least one annular piston with a sleeve.
 3. Forming device according to claim 1, further comprising at least one thrust collar and/or at least three thrust pins.
 4. Forming device according to claim 2, further comprising at least one plunger.
 5. Forming device according to claim 1, wherein at least one of the first and second clamping devices communicates with at least one bladder accumulator.
 6. Forming device according to claim 1, further comprising at least one counter plunger.
 7. Forming device according to claim 1, further comprising at least one ejector pin.
 8. Forming device according to claim 2, further comprising at least one thrust collar and/or at least three thrust pins.
 9. Forming device according to claim 8, further comprising at least one plunger.
 10. Forming device according to claim 5, where at least one of the at least one first and second clamping device has at least one annular piston with a sleeve.
 11. Forming device according to claim 10, further comprising at least one thrust collar and/or at least three thrust pins.
 12. Forming device according to claim 11, further comprising at least one plunger.
 13. Forming device according to claim 6, where at least one of the at least one first and second clamping device has at least one annular piston with a sleeve.
 14. Forming device according to claim 13, further comprising at least one thrust collar and/or at least three thrust pins.
 15. Forming device according to claim 14, further comprising at least one plunger.
 16. Forming device according to claim 7, where at least one of the at least one first and second clamping device has at least one annular piston with a sleeve.
 17. Forming device according to claim 16, further comprising at least one of at least one thrust collar and at least three thrust pins.
 18. Forming device according to claim 17, further comprising at least one plunger.
 19. Forming press, comprising a forming device according to claim
 1. 20. Forming press according to claim 19, comprising at least one ram and at least one platen.
 21. Forming press according to claim 19, further comprising at least one of at least one ram ejector rod and at least one platen ejector rod.
 22. Forming method, comprising using at least one of a device according to claim 1 and a press according to claim
 19. 